iOS: To-do lists can help you focus, but they're primarily an individual activity. Complete is a to-do list that harnesses the power of others to keep you accountable and motivated.
Complete's public to-dos can be useful for gathering information. For example, if one of your to-dos is to make dinner, you can ask the community for ideas. People will suggest dishes or recipes in the comments. Naturally, you can also set private to-dos for any activities that you'd prefer to keep under wraps.
You can follow specific users on Complete. Their to-dos will appear in your feed. So far, I've noticed that users come from a pretty diverse set of places (although I haven't found any in Toronto). I imagine Complete will become much more useful as more local users come online and can share information or meet up in the physical world.
Most importantly, you can invite your friends from Facebook and Twitter to join and help you stay motivated and accountable to your goals. Although it sounds like a simple technique, even just telling two or three close friends can fuel your progress towards your goals.